1. Field of the Invention
The present invention relates to a double effect absorption cold or hot water generating machine, and more particularly to a double effect absorption cold or hot water generating machine which can supply hot water from a water heater even when it is used for a cooling operation.
2. Description of the Related Art
Conventionally, in a cold or hot water generating machine which can supply cold water and hot water simultaneously, it has been customary to use a system in which refrigerant vapor in a high temperature generator is introduced into a water heater where the refrigerant vapor is condensed to generate heat of condensation and hot water is produced. The hot water capacity is controlled by adjusting the amount of refrigerant liquid which is stored in the water heater. In this system, the utilized principle is that heat transfer with condensation is carried out at portions of the heat exchanger tubes which are not immersed in refrigerant liquid to thus effect large heat transfer, but poor heat transfer is effected at portions of the heat exchanger tubes which are immersed in refrigerant liquid. That is, effective heat transfer areas are adjusted by refrigerant liquid to control the amount of produced hot wafer.
In this system, in the case where the load of hot water is extremely small, even if the entire areas of the heat exchanger tubes are immersed in refrigerant liquid, in some cases, the output of hot water is larger than the load of hot water. To be more specific, even if the entire areas of the heat exchanger tubes are immersed in refrigerant liquid, refrigerant vapor is generated in the high temperature generator due to the load of cold water, the generated refrigerant vapor is condensed at the surface of refrigerant liquid in the water heater, and the heat of condensation is transmitted to hot water through the refrigerant liquid. Therefore, the temperature of hot water rises gradually to reach a value higher than the target temperature. Further, energy generated in a hot water pump is given to hot water to cause the temperature rise of hot water.